Semiconductor devices and opto-electronics
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Transcript of Semiconductor devices and opto-electronics
Semiconductor devices and opto-electronics
Meint Smit
Leon Kaufmann
Xaveer Leijtens
Opto-Electronic Devices GroupEindhoven University of Technology
2
Course information
• Opto-electronics:– Book: Gerd Keiser, Optical Fiber Communications
3rd edition, McGraw-Hill, obligatory!– Contact: Xaveer Leijtens
[email protected] – 247 5112
• Electronic devices:– Book: Linda Edwards-Shea, The Essence of Solid-
State Electronics, Prentice Hall, obligatory!– Contact: Leon Kaufmann
[email protected] – 247 5801
• Website: http://oed.ele.tue.nl (education)
3
Course overview
Week Mon 1,2 Tue 1,2 Wed 2,3 Fri 2 (vko) Fri 3,4
49 Lect o Lect e Instr o Lect e Lect o
50 Lect e Instr e Instr o Lect e Lect o
51 Lect e Instr e Instr o Lect e Lect o
2 Lect e Instr e Instr o Lect e Lect o
3 Lect e Instr e Instr o Lect e Instr e
4
Contents semiconductor devices
• Recapitulation: electrons in atoms, introduction to quantum mechanics
• Solid state materials: crystal structures, energy band diagrams of insulators, metals and (un)doped semiconductors
• Semiconductors and carrier transport• Principle of operation of pn junction diodes• Fundamentals of MOSFETs• CMOS technology (incl. video demonstration)
5
OGO3.2Free space optical communication
Kickoff Meeting Dec 1 in MA1.41 13:30h
6
Contents Opto-Electronics
Lecture Chapter About
1 1 Introduction
2 Optical fibers
2 3 Fiber transmission properties
5 Power launching and coupling
3 4 Light sources
4 6 Light detectors
5 7 Optical receivers + guest lecture
7
Examination
• Closed-book examination, formula sheet will be provided• Electronic devices: Edwards-Shea, chapter 1-8• Opto-electronics: Keiser
Chapter # pages
1 not: 1.4 and 1.5 15
2 not: 2.3.5, 2.4.3-9, 2.7.2-4, 2.8-10 30
3 3.1.2-3.1.4: no formula’s, only mechanismsnot: 3.1.5, 3.3, 3.4, 3.5.4-5
28
4 not: 4.4 and 4.5 44
5 not: 5.1.3, 5.2.1-end, with p 212, 218 8
6
7
8
Optical communication
+ ––
TRANSMITTER FIBRE
+ –
RECEIVER
9
Electromagnetic spectrum
• Optical communication wavelength: = 1500 nmcorresponds to = c/ 200 THz = 200.000 GHz
• 1% = 2 THz = 2000 GHz• EDFA-bandwidth 30 nm 4 THz
10
Standard Single-Mode (SM) Fiber
Fiber coreSiO2+ GeO2
Ø 10 mn 1.443
SiO2 Cladding
Ø 125 mn 1.44
Primary coating (soft)Ø 400 m
Secondary coating (hard)Ø 1 mm
11
Optical source
+ ––
TRANSMITTER
FIBER
Performance
Modulation speedFiber-coupled power
12
–
Light Emitting Diode (LED)
Typical performance data
Power in MM-fiber: 100 W
Power in SM-fiber: 1 W
Direct Modulation Bandwidth: 100 MHz
+
13
Laser
Typical performance
Power (in fiber): 5-10 mWMax: 100-300 mWDirect Modulation Bandwidth: 1-10 GHz
14
Photodiode detector
Typical performance data
Responsivity: ~1 mA / mWBandwidth: 1-20 GHz
+ –
15
Optical communication systems
First Generation, ~1975, 0.8 mMM-fiber, GaAs-laser or LED
Second Generation, ~1980, 1.3 m, MM & SM-fiberInGaAsP FP-laser or LED
Third Generation, ~1985, 1.55 m, SM-fiberInGaAsP DFB-laser, ~ 1990 Optical amplifiers
Fourth Generation, 1996, 1.55 mWDM-systems
1.80.8 1.0 1.2 1.4 1.60.9 1.1 1.3 1.5 1.7Wavelength (m)
Att
en
ua
tion
2 dB/cm
16
WDM-transmission
MultiwavelengthTransmitter
MUX
MultiwavelengthReceiver
DMX
opticaltransmitter
opticalreceiver
optical fiber
+ –
17
Erbium-Doped Fiber Amplifier (EDFA)
PUMP LASER 0.98 m or 1.48 m
Er-doped fiber
MUX FILTER
-10
0
10
20
30
1520 1530 1540 1550 1560 1570
wavelength (nm)
ED
FA
ga
in (
dB
)
18
Synchronous Digital Hierarchy
Data rate SDH
Europe
SONET
US & Japan
52 Mb/s OC-1
155 Mb/s STM-1 OC-3
622 Mb/s STM-4 OC-12
2.5 Gb/s STM-16 OC-48
10 Gb/s STM-64 OC-192
40 Gb/s STM-256 OC-768
EuropeSDH: Synchronous
Digital Hierarchy
STM: SynchronousTransport Module
US & JapanSONET: Synchronous
Optical Network
OC: OpticalCarriers
19
WDM experiments
Si electronics
ETDM
installed(10x / 6 yrs)
(10x / 2.5 yrs)
5 yrs
0.01
0.1
1
10
100
1000
10000
1980 1985 1990 1995 2000
Cap
acit
y (G
b/s
)
Trunk transmission capacity
20
# W
DM
-cha
nnel
s
4
16
64
256
0.01 0.1 1 10 100
Channel bitrate (Gb/s)
1
Trunk transmission capacity
•‘97
10 Gb/s
1 Tb/s
0.1 Gb/s
1 Gb/s
100 Gb/s
•‘98
•‘98•
‘99
•‘00
•‘04?
•‘86
•‘96
•‘89
•‘83
•‘80
21
Undersea cables
22
Undersea cable
Cable Capacity fully upgraded (Gbps)
2,400
Fiber Pairs 6
Wavelengths per Fiber Pair 40
Gbps per Wavelength 10
Cable Length (km) 14,500
23
Optical Transport Network
Global Network
Wide Area Network
Metropolitan/Regional Area Optical Network
Corporate/Enterprise Clients
Cable modemNetworks
Client/Access Networks
FTTHMobile
SDH/SONET
ATM
PSTN/IP
ISPGigabit Ethernet
Cable
FTTB
ATM
< 10000 km< 10 Tbit/s
< 100 km< 1 Tbit/s
< 20 km100M - 10 Gbit/s
Courtesy: A.M.J. Koonen
24
O X C
1
2
1
2
in out
X
X
X
X
Integrated optical cross-connect
Dimensions: 8x12 mm2
25
Fibre propagation
n1
n2
26
Fiber performance
z=0 z=L
Dispersion
z=0 z=L
Attenuation
27
Optical attenuation in glass
1960
Att
enua
tion
(dB
/km
)
1
10
100
1000
0.11970 1980 1990 2000
20 dB/km (Corning)
0.16 dB/km
CVD (Chemical Vapor Deposition)
28
1.80.8 1.0 1.2 1.4 1.60.9 1.1 1.3 1.5 1.7
Wavelength (m)
Att
enua
tion
(dB
/km
)
0.2
0.5
1.0
1.5
0.16 dB/km
Rayleighscattering
IR band edge
OH--peak
UVabsorption
0.70.6
Fiber attenuation (SiO2)
29
A note on dB and dBm
• dB– optical signals:
– electrical signals:
–
• dBm– absolute power value (with 1 mW as reference)
– power level in dBm:
2
1log10P
P
22
11
2
1
2
1 log10log20log20IV
IV
I
I
V
V
mW
P
1log10
elelopt PIP electrical dB = 2 x optical dB
30
Reflection & refraction
n2<n1
n1
1 1
1
2
2
Snell’s law
2211 sinsin nn
2211 coscos nn
n2<n1
n1
1= c
c
Critical angle
1
2sinn
nc
1
2cosn
nc
n2<n1
n1
1 >c
Total internal reflection
31
Numerical Aperture
1
2cosn
nc Critical angle:
Maximum entrance angle:
cn
n sinsin0
1max,0
Multimode fiber
n1
n2
0
c
n0
n0
22
21
211max,00 cos1sinsin nnnnnNA cc
Numerical aperture:
n
n
n
nn
n
nn
nnn
1
212
1
22
21
21
2
: if 222
22
1 nnnnnNA
61.0 max,0NA
32
L
n1
n2
Dispersion (intermodal)
c
t
c
n
n
nL
T
2
1
c
nLT 1
min
cc
nLT
cos1
max
1
2cosn
nc
c
n
c
n
n
nL
T
2
1
nc
NA
c
n
c
n
n
nL
T2
2
2
1
T
LLB
2
2
NA
nc
T
LLB
kmnsnc
NA
c
n
c
n
n
nL
T /2
2
2
1
kmsMbNA
nc
T
LLB )/(
22
33
Bandwidth and bit rate
tT
FWHM
dBo
0
1.5
3
oe
dBe
0
3
6
oe
e
CCT
B
22
1120
Rule of thumb:
(incoherent)
Bandwidth
Cross talk
opteldet PPI
34
refractiveindex
SM Single-Mode
Fiber types
MM-SIMulti-ModeStep Index
MM-GIMulti-ModeGraded Index
2/1
1 21
a
rnrn
35
Fiber classification (1)
Core diameter 50 - 400 m
Cladding 125 (500) m
2nd coating 250 - 1000 m
NA 0.16 - 0.5
Attenuation 1 - 4 dB/km
Bandwidth 6 - 25 MHz.km
Application Short distance, low cost
limited bandwidth
MM-SI: Multi Mode - Step Index fiber
36
Fiber classification (2)
Core diameter 50 m standard
Cladding 125 m
2nd coating 200-1000 m
NA 0.2 - 0.3
Attenuation 1 dB/km (1300 nm)
Bandwidth 150 MHz.km - 2 GHz.km
Application Medium distance communication
LED/Laser sources
MM-GI: Multi Mode - Graded Index fiber
37
Fiber classification (3)
Core diameter 3-10 m
Cladding 50-125 m
2nd coating 200-1000 m
NA ~0.1 (not used)
Attenuation 0.20@1550 - 0.4@1300 dB/km
Bandwidth >> 500 MHz.km
Application Long distance communication
Lasers, standard fiber
SM-SI: Single Mode - Step Index fiber
38
The wave equation
Plane wave:
Spherical wave:rjkeE
R
eE
Rjk
Solutions to Maxwell’s equations:
2
kn
knk
/0
0
r
rr
n
kk
0000
phase fronts
39
Wave vector and decomposition
kz
kx
kkx
kz
z
x
z
x
zjkxjk zx eezxE ),(
zz
xx
k
k
2
2
40
Interference
x
x
z
z
phase frontsabsorber
metallic plates
kz
kx
k+
kx+
kz
+
kx-
k-
-
zjkx
zjkxjkxjk
rkjrkj
z
zxx
exk
eee
eezxE
cos2
,
xx
xz
k
nkk
kkk
2
0
22
41
The metallic waveguide
metallic plates
d
z
x
kz zj
x exkzxE cos,
dx 2x
xk 2
220
2xz kknk
42
Modes & Rays
waveguide
d
2 1 0
m=0 m=2m=1
d
mk mx
1,
0
,arcsinnk
k mxm
43
Optical waveguide modes
m=0 m=4m=3m=2m=1
n2
n1
n0
k
z
m=0m=1
m=2m=3
m=4
kx
n1k0
c2
c0
substrate modes
superstrate modes
guided modes
n0k0n2k0 n1k0
44
Mode intensity profiles
• Optical modes:
• Excitation of modes:
0 1 2
d
a
Planar:
Single-mode if V
Fiber:
Single-mode if V 2.405
22
21
2nn
dV
22
21
2nn
aV
45
V-parameter
• V number: determines how many modes a fiber supports
• Lowest order mode HE11 has no cut-off
• Single-mode fiber:
NAa
nna
V
22 2
22
1
405.2V
46
Number of modes
• Number of modes in step-index fiber
• Optical power in the cladding
2
2
2
1 22
22
1
2V
nna
M
MP
Pcladding3
4 for large values of V
47
Step index fiber modes (2)
Effective index /k as a function of
Single-mode fiber: V 2.405
NAa
nna
V
22 2/12
22
1
HE11
TE01TM01
EH11
HE12
HE31
0 1 2 4 53 6
n1
n2
k
48
Birefringence
• HE11:
• Birefringence: difference in effective refractive indices between two polarization modes
• Fiber beat length: phase difference between the two polarization modes is
xyf nnB
xyp nnk
L
0
Horizontal modeVertical mode
49
Fiber materials
• Silica glass fiber– starting material: pure silica (SiO2) in the form of fused quartz
(amorphous)– modification of refractive index by addition of impurities
• lowering refractive index : B2O3, F• raising refractive index : P2O5, GeO2
• Polymer optical fiber (POF)– large core (multimode)– large refractive index difference between core and cladding– easy handling– relatively high losses
50
Losses in polymer optical fiber
• Absorption loss in POF >>> Absorption loss in Silica fiber search for low loss polymers
• PMMA (Poly Methyl Metacrylate)• PS (Polystyrene)• FA (Fluoro acrylate)
– Typical absorption levels: 100 dB/km– Low loss windows: several windows in the range 500-800 nm
• New material development: perfluorinated polymer 50 dB/km from visible to 1600 nm
• Core type• Step index• Graded index
51
Advantages of Optical communication
Huge bandwidth
Small and light
Low loss
Electrical isolation
No EMI (Lightning, interference)
Security (no tapping)
Reliability
Low cost per bit